Perf test of looping through Headers from http://stackoverflow.com/questions/6439225/how-to-loop-through-webheadercollection

header-loop-perf.cs

void Main()
{
	var headers = new System.Net.WebHeaderCollection();
	headers.Add("xxx", "yyy");
	headers.Add("zzz", "f&&ff");
	headers.Add("xxx", "ttt");
	headers.Add("yyy", "33,3");
	
	headers.Dump("raw");
	headers.ToString().Dump("string'd");
	dumpHeaders(headers);
	
	toTuple(headers).Dump("Tuples");
	toDict(headers).Dump("Dict");	
	toArray(headers).Dump("Array");	

	// dumps results and timestamps for each "test"
	new Perf<object> {
		{ "dict", n => (object) loop(toDict(headers)) },
		{ "array", n => (object) loop(toArray(headers)) },
		{ "enumerable", n => (object) loop(toEnumerable(headers)) },
		{ "tuple", n => (object) loop(toTuple(headers)) },
	}.Vs("Loop All");

	// dumps results and timestamps for each "test"
	new Perf<object> {
		{ "dict", n => (object) loop(toDict(headers), shortCircuit) },
		{ "array", n => (object) loop(toArray(headers), shortCircuit) },
		{ "enumerable", n => (object) loop(toEnumerable(headers), shortCircuit) },
		{ "tuple", n => (object) loop(toTuple(headers), shortCircuit) },
	}.Vs("Premature stop");
}

// Define other methods and classes here
bool shortCircuit<T>(T instance) { return true; }

T loop<T>(IEnumerable<T> list, Func<T, bool> stop = null) {
	T result = default(T);
	foreach(var o in list) {
		result = o;
		if(null != stop && stop(result)) break;
	}
	return result;
}

Dictionary<string, string[]> toDict(System.Net.WebHeaderCollection headers) {
	return Enumerable.Range(0, headers.Count).ToDictionary(i => headers.Keys[i], headers.GetValues);
}
IEnumerable<KeyValuePair<string, string[]>> toEnumerable(System.Net.WebHeaderCollection headers) {
	foreach(var key in headers.AllKeys) {
		yield return new KeyValuePair<string, string[]>(key, headers.GetValues(key));
	}
}
KeyValuePair<string, string>[] toArray(System.Net.WebHeaderCollection headers) {
	string[] keys = headers.AllKeys;
	var keyVals = new KeyValuePair<string, string>[keys.Length];
	for (int i = 0; i < keys.Length; i++)
		keyVals[i] = new KeyValuePair<string, string>(keys[i], headers[keys[i]]);
	return keyVals;
}
IEnumerable<Tuple<string, string>> toTuple(System.Net.WebHeaderCollection headers) {
	return Enumerable
                .Range(0, headers.Count)
                .SelectMany(i => headers.GetValues(i)
                .Select(v => Tuple.Create(headers.GetKey(i), v)));
}

void dumpHeaders(System.Net.WebHeaderCollection headers) {
	for(int i = 0; i < headers.Count; ++i) {
		string header = headers.GetKey(i);
		foreach(string value in headers.GetValues(i)) {
			Console.WriteLine("{0}: {1}", header, value);
		}
	}
}